Traffic barriers

Abstract

 A traffic barrier comprises a step-like obstruction (1) able to prohibit flow of vehicles through the barrier in either direction, a hinged platform (8) disposed adjacent the step-like obstruction and rockable between a lowered position and a raised position, in which its trailing edge (11) is adjacent the top of the step-like obstruction, springs (12) urging the platform into its raised position, latch means (15) operable to lock the platform in its raised position, and control means, including a coin-operated device orthe like located in advance of the leading edge (9) of the platform, for actuating the latch means and locking the platform in its raised position so as to permit a vehicle to advance overthe step-like obstruction from rightto left. The control means is responsive to advance of the rearmost wheels of the vehicle on to the top of the step-like obstruction to release the latch means and prevent advance of a following vehicle until the coin-operated device istripped by the driver of the following vehicle.

Description

[0001] The present invention relates to traffic barriers and, more particularly, although not exclusively, to traffic barriers for controlling the exits or entrances to car or vehicle parks.

[0002] Existing barrier constructions for controlling the flow of vehicle traffic generally comprise either a hinged arm, which is adapted to be lowered across the path of an approaching vehicle or, alternatively, a hinged or raisable step or plate, which is disposed at ground level and can be moved into a position to obstruct the wheels of an approaching vehicle.

[0003] It is customary to open such a barrier by lodging the appropriate fee in a coin-operated control mechanism or by actuating the control mechanism with a token, ticket or card. This effects opening of the barrier to permit passage of the vehicle which automatically actuates the control mechanism to close the barrier after it has negotiated the barrier.

[0004] In either type of existing barrier, the barrier, itself, is moved into its operative position by some form of motive device, such as, an electric motor or a hydraulic or pneumatic cylinder. The motive device is operated each time the barrier is opened and closed. When the barrier is used for a car park, the barrier and ancillary equipment are operated every time a vehicle is permitted to pass the barrier and this may require frequent actuation of the barrier and its ancillary equipment. Hence, existing barrier constructions require appreciable quantities of mechanical and electrical control equipment, may be subject to considerable wear, and tend to consume undesirable amounts of energy. A further disadvantage of existing constructions is that they do not reliably restrict the flow to one vehicle upon each operation of the barrier and can permit the unauthorised passage of an additional vehicle, when opened.

[0005] It is an object of the present invention to provide a traffic barrier which utilizes simpler operating mechanism than hitherto known barriers, is less expensive to operate, and reliably restricts the flow of vehicles to one vehicle for each operation of the barrier device.

[0006] The invention consists in a traffic barrier comprising a step-like obstruction adapted to resist or prohibit the passage of a vehicle, a hinged platform disposed in advance of the step-like obstruction and rockable between a lowered position and a raised position, in which its trailing edge is adjacent the top of the step-like obstruction;, and means urging the platform into its raised position, characterised by the platform being depressible into its lowered position by a vehicle advancing over said platform from its leading to its trailing edge, whereby the obstruction is presented to the vehicle to resist its advance, latch means operable to lock the platform in its raised position, and control means for selectively actuating the latch means, whereby the platform may be locked in its raised position to permit a vehicle to advance over the obstruction from the platform, said control means being responsive to advance of the rearmost wheels of the vehicle onto the top of the obstruction to release the latch means.

[0007] With the present invention, the step-like obstruction is capable of prohibiting passage of vehicles through the barrier in either direction. Moreover, the platform is normally urged, for example, by spring means, into its raised position and there is no obvious, visible obstruction to the advance of a vehicle. When the prescribed action is taken to signal the control means to actuate the latch means, for example, by lodging the appropriate parking fee in a coin-operated control mechanism for the barrier, the platform is locked in its raised position to permit the vehicle to advance over the step-like obstruction. On the other hand, if the prescribed action is not taken, as soon as the vehicle moves on to the hinged platform, its weight depresses the trailing edge of the platform, which moves to its lowered position, so that the step-like obstruction is presented to the vehicle and prohibits its advance. It will be appreciated that for every vehicle permitted to proceed past the barrier, the platform is
locked in its raised position and there is consequently no movement of the barrier. In practice, the platform only moves on rare occasions, so that the barrier mechanism is subject to little wear, and the barrier only requires a small amount of energy to operate the latch means, thus resulting in a considerable reduction in operating and maintenance costs. Immediately, the rearmost wheels of a vehicle have advanced from the platform on to the top of the step-like obstruction, the control means may be actuated to release the latch means so that a following vehicle, for which the prescribed action has not been taken, will depress the platform and be obstructed by the barrier which, consequently, provides for strict control over the flow of vehicles.

[0008] Furthermore, the rate at which vehicles can negotiate a barrier according to the invention is appreciably greater than that for existing barriers since no delay is experienced in raising and lowering a barrier device. The speed of operation of a barrier according to the invention can be further increased, with a view to permitting vehicles to pass with a minimum of delay, by constructing the control means to accept payment of the prescribed fee or read a card or ticket whilst the preceding vehicle is still travelling over the platform.

[0009] In one embodiment of the invention, the step-like obstruction is arranged to project above an adjacent road surface and the platform is arranged as a ramp which leads from the road surface to the top of the obstruction, when in its raised position. A fixed ramp is disposed on the opposite side of the obstruction to the platform and extends downwardly from the obstruction to the road surface in order to permit a vehicle to return to the normal road surface after it has negotiated the barrier.

[0010] In another embodiment, the barrier may be disposed in an excavation in a road or track with the top of the step-like obstruction substantially level with the adjacent road surface and the platform, when in its raised position, also substantially level with this road surface.

[0011] Preferably, the step-like obstruction and the hinged platform are prefabricated as two separate units which can be installed in juxtaposed relation, either on an existing road surface or in an excavation in the road, in order to construct the traffic barrier. For the former arrangement, the exit ramp from the barrier may also be manufactured as a prefabricated unit which can be installed contigously with the rearside of the unit forming the step-like obstruction.

[0012] The control means may include a coin, token, card or ticket operated device positionable in advance of the hinged platform and responsive to the insertion of one or more prescribed coins or tokens or to the scanning of a prescribed ticket or card to actuate the latch means and lock the platform in its raised position. For releasing the latch means after the rearmost wheels of a vehicle have advanced onto the step-like obstruction, the control means may include detecting means disposed on or adjacent the step-like obstruction and responsive to the advance of the rearmost vehicle wheels on to the top surface of the obstruction.

[0013] When the traffic barrier is located at a site where it must allow free flow of vehicles in the reverse direction, such as, at the common entrance and exit to a car park, the control means may include first auxiliary detecting means disposed rearwardly of the step-like obstruction and arranged to detect the front wheels of a vehicle travelling in the reverse direction, whereupon to actuate the latch means so as to lock the platform in its raised position, and second auxiliary detecting means disposed forwardly of the leading edge of the platform and operable by the rearmost wheels of a vehicle so as to release the latch means, thereby permitting unhindered flow of vehicles in said reverse direction.

[0014] Both the main and auxiliary detecting means may comprise actuating means movable by the wheels of a vehicle negotiating the barrier and adapted to actuate switch means. For example, in one embodiment, the main detecting means comprises actuating means mounted on the top of the step-like obstruction and movable by the wheels of a vehicle travelling on the top surface of the obstruction to actuate switch means which is responsive to movement of the actuating means by the rearmost wheels of the vehicle in order to release the latch means.

[0015] Preferably, the latch means comprises at least one solenoid-operated latch member mounted on the step-like obstruction and arranged to engage a cooperating detent on the platform, when the latter is in its raised position. The latch member may be controlled by two solenoid devices, one of which is adapted to advance the latch member into its locking position and the other of which is adapted to retract the first solenoid device and the latch member to their release positions. With this arrangement, only momentary energization of each solenoid device is required to move the latch member in opposite directions so that the energy consumption of the barrier is minimised.

[0016] Conveniently, the latch means incorporates a fail safe device which is adapted automatically to actuate the latch means and lock the platform in its raised position when the electrical supply is switched-off or in the event of failure of the electrical supply.

[0017] A visual signal may be associated with the barrier in order to provide the driver of a vehicle with a visible indication of whether or not the platform is locked in its raised position and the vehicle is authorised to proceed. Such a visual signal may be in the form of conventional red and green traffic lights illuminated under the control of the control means. However, in some cases it may, alternatively or in addition, be desirable to provide an actual visible barrier in the path of travel of a vehicle negotiating the barrier, since the latter may not be apparent until unauthorised advance of a vehicle depresses the platform. Because a driver of a vehicle normally may see nothing to prevent him from negotiating the barrier, it is possible that he may be tempted to risk driving through the barrier without first paying the appropriate fee or taking other prescribed action. Accordingly, a visible barrier member, for example, in the form of a flap or board, may be mounted on the step-like obstruction and be operable by the control means so as to move into a visible position on the top of the obstruction when the latch means is released or disengaged and to return to a concealed, or substantially concealed, unobstructing position when a vehicle driver has taken the prescribed action to permit him to proceed.

[0018] In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which:-

Fig. 1 is a plan view of one embodiment of the invention,

Fig. 2 is a side elevation of the embodiment shown in Fig. 1,

Fig. 3 is a fragmentary cross-sectional view illustrating a preferred form of the latch mechanism,

Fig. 4 is a block schematic diagram of a preferred form of control circuitry for the barrier, and

Fig. 5 is a side elevation of a second embodiment.

[0019] Referring to Figs. 1 and 2 of the drawings, the traffic barrier is shown installed on a road surface R and comprises a central barrier or obstruction unit 1 in the form of a step-like obstruction, a hinged platform unit 2 disposed ahead of the step-like obstruction, and a fixed ramp unit 3 disposed rearwardly of the obstruction. The units 1 and 2 have metal supporting frameworks, indicated schematically in outline at 4 and 5, respectively, of any suitable construction, and the sides of the frameworks may be suitably encased with cladding (not shoivn). The unit 1 has a top surface 6, over which a vehicle may travel, and a solid front wall 7 which together form the step-like obstruction. The hinged platform unit 2 is constructed as a ramp and comprises a platform 8 hinged, at or adjacent its leading edge 9, to its supporting framework 5 by trunnions 10. The trailing edge 11 of the platform is disposed closely adjacent the front wall 7 of the step-like obstruction and the platform is rockable about the trunnions 10 from a lowered position, in which its trailing edge 11 is located adjacent the bottom of the front wall 7 to a raised position in which the trailing edge is substantially level with the top surface 6 of the obstruction. The platform 8 is urged into its raised position by heavy duty leaf springs 12 located adjacent opposite sides of the platform. Each of these leaf springs is bolted at one end to the supporting framework 5 and, at its opposite ends, bears against the underneath of the platform 8. The platform is indexed in its raised position by detent members 13 disposed at opposite ends of its trailing edge 11 which engage underneath frame members 14 of the obstruction unit 1 (see Fig. 3). Mounted at opposite sides of the obstruction unit adjacent the top of its front wall 7 are two latch mechanisms, generally indicated at 15, which are engagable underneath the detents 13, when these are in abutting relation with the frame members 14, to lock the platform in its raised position, as will be more fully described hereafter. Mounted adjacent the rear side of the obstruction unit and extending substantially across the full width of this unit so as to lie in the track of a vehicle travelling over the unit 1 is a detecting mechanism, which includes a switch 16 and which will also be more fully described hereafter, for controlling release of the latch mechanisms 15 after a vehicle has negotiated the barrier.

[0020] The fixed ramp unit 3 may be constructed in situ or may be prefabricated. It comprises a horizontal surface portion 17 contiguous with the top surface 6 of the unit 1 and leading to a downwardly extending ramp portion 18 via which vehicles travelling over the barrier return to the normal road surface R on which the barrier is installed. If necessary, short lead-in and lead-out sections 19,20 may be installed at the leading and trailing ends of the units 2 and 3, respectively, to afford smooth travel of a vehicle from the normal road surface R on to the barrier and vice versa.

[0021] At the site where the barrier is installed, suitable arrangements are made to ensure that a vehicle travelling along the road R controlled by the barrier, from right to left, as viewed in Figs. 1 and 2, must proceed via the barrier units. The latter are made of adequate width to accommodate any vehicle expected to use the barrier. The horizontal surface at the apex of the barrier formed by the top surface 6 of the unit 1 and the contiguous surface portion 17 of the fixed ramp unit 3 enables the ramp units 2,3 and, hence, the overall barrier, to be kept reasonably short, whilst providing an adequate depth for the front wall 7 of the obstruction unit 1, without risk of the underside of a vehicle wedging against the apex of the barrier.

[0022] Referring to Fig. 3, each latch mechanism 15 includes a latch member 21 slidably mounted in a housing 22 secured to the underneath of a frame member 23 of the obstruction unit 1 adjacent the path of movement of the associated detent 13 on the platform. The latch member is actuated by two solenoids S1,S2 connected in series and disposed in a protective housing 24 secured below the top surface of the unit 1. The latching solenoid S1 has its armature 25 linked to the adjacent end of the slidable latch member 21 by a coupling rod 26 which is slidably mounted in a bracket 27 supported inside the housing 24 and which projects through a gasket 28 located at the adjacent end of the h_Qusing. The rod 26 is pivotally connected at its opposite ends to the armature 25 and the latch member, respectively. The releasing solenoid S2 is adapted to retract the armature 25 and the latch member from their locking positions. It is mounted rearwardly of the solenoid S1 and has its armature 29 connected to the rear end of the armature 25 by a link 30 so that the solenoids are coupled in series. Mounted in the housing 24 rearwardly of the solenoid S2 is a fail-safe solenoid S3. The armature 31 of the latter is aligned with the armature 29 of the solenoid S2 and is resiliently urged towards the adjacent, rear end of the armature 29 by tension springs 32 connecting a yoke 33, secured to the armature 31, to the casing of the solenoid S2. When the electrical current is switched on and the barrier is operating normally, the armature 31 of the solenoid S3 is retracted to permit the armature 29 to reciprocate freely as the latch member 21 is advanced and retracted by the solenoids S1 and S2. When the current is switched-off, or there is a failure in the electrical supply, the armature 31 is urged against the armature 29 by the springs 32 and drives the armature 29 and, in turn, the armature 25 and the coupling rod 26, in a direction to slide the latch member 21 into its locking position, where it is retained by the springs so as to hold the platform in its raised position and prevent the inoperative barrier from obstructing flow of vehicles.

[0023] The operation of the barrier will now be described in conjunction with Fig. 4 which schematically illustrates one form of control circuitry for the barrier. The particular circuitry illustrated is intended for controlling the barrier when installed at the entrance or exit to a car park. It includes a coin-operated switch device 34 housed in a cubicle or meter (not shown) located ahead of the hinged platform unit 2 of the barrier, in a convenient position for insertion of the prescribed parking fee by the driver of a vehicle wishing to negotiate the barrier. Red and green traffic lights 35,36 are also located in a convenient position to be observed by the driver to signal the driver when the platform is locked in its raised position and he is authorised to proceed. The device 34 is connected to a convenient alternating current supply 37 and, when this is switched-on to permit the barrier to operate, the fail-safe solenoids S3 are energized, via the lines 34a, 34b, so that the armatures 31 are retracted, and the solenoids S2 are momentarily energized so that the latch members 21 are retracted from their locking positionso The red traffic light 35 is illuminated via a double pole microswitch 38 which is connected to the line 34a and is arranged to be actuated by the armature 25 of one solenoid S1 (see Fig. 3). The platform 8 is now in the unlocked condition and, if a vehicle driver attempts to drive his vehicle through the barrier without first lodging the required fee in the coin controlled mechanism, the platform 8 will be depressed by the weight of the vehicle to the position shown in broken lines in Fig. 2 and continued advance of the vehicle will be opposed by the physical size of the obstruction presented by the front wall 7 of the step-like obstruction 1. In order to negotiate the barrier, the vehicle driver must insert the prescribed parking fee in the coin controlled device 34, whereupon the latter momentarily energizes the latching solenoids S1, via the line 49, so as to advance the latch members 21 and lock the platform in its raised position. Simultaneously, movement of the armature 25 of the one solenoid S1 actuates a microswitch 39, which is juxtaposed the microswitch 38, so that the electrical supply is connected, via the line 40, to the two sets of switch contacts 41,42 controlling release of the latches, and enables the relay R1 for this purpose. It also actuates the microswitch 38 to switch-off the red traffic light and illuminate the green light, thereby authorising the driver to proceed. When the vehicle has advanced onto the top 6 of the step-like obstruction and its rear wheels have left the platform 8, the latches must be released to prevent passage of a subsequent vehicle. This is effected by the switch actuating bar 16 in conjunction with the two sets of switch contacts 41,42.The actuating bar 16 is hinged about an axis 43 extending transversely to the step-like obstruction with its top edge projecting above the top surface 6 of the obstruction so as to be engageable by the wheels of a vehicle travelling over this surface. The actuating bar is resiliently urged into an upright position by one or more tension springs 44 connected to the lower edge of the bar. When the front wheels of the vehicle engage the actuating bar, it is rocked in an anti-clockwise direction, as viewed in Fig. 4, and the bar sequentially closes the switch contacts 41,42. The switch contacts 41 are connected, via a line 45, to energize a relay R2 which actuates the release solenoid S2. The switch contacts 42, via a line 46, control energization of the relay R1 which, in turn, enables the relay R2. Hence, when the switch contacts 41 are triggered for the first time upon movement of the front wheels of a vehicle over the actuating bar 16, these contacts are isolated from the solenoid S2 and the latter is therefore not energized and the latches remain in their locking positions. When the actuating bar subsequently triggers the switch contacts 42, the relay H1 is energized to enable the relay R2, via the line 47, and is retained in this condition by associated hold-in contacts. When the front wheels of the vehicle disengage the actuating bar, it returns to its upright position, permitting the switch contacts 42 to open. This has no affect because the relay R1 is maintained energized via its hold-in contacts and the switch contacts 41 are operable only unidirectionally so that the return movement of the actuating bar does not close these latter switch contacts. The control circuitry is now conditioned to release the latches and, when the rear wheels of the vehicle engage the actuating bar 16 and the switch contacts 41 are again triggered, the relay IZ2 is energized. The latter is retained in this condition by associated hold-in contacts and, in turn, energizes the solenoids S2 which retract the latch members 21 and unlock the platform. As the latch members and solenoid armatures 25 are retracted by energization of the solenoids S2, the microswitches 38,39 are restored to their initial positions so that the electrical supply is immediately disconnected from the switch contacts 41,42 and the relays R1,R2, which are de-energized, and the green traffic light is switched-off whilst the red light is switched-on to indicate to a following vehicle that the barrier is closed and that it is not authorised to proceed.

[0024] It is desirable that the barrier should be capable of operating as rapidly as possible so as to allow vehicles to pass with minimum delay. The maximum speed of operation of the barrier can be increased by enabling prepayment of the parking fee while the preceding vehicle is still advancing over the platform 8. It is customary to operate existing car park barriers with what is commonly known in the art as a coin verifier or coin rejector. In such equipment, the coins inserted into the parking meter travel down an inclined chute into the coin verifier. The device 34 may include a coin verifier of known type but modified so that, as soon as the coins operate the latch mechanisms, upon successfully passing through the verifier, an auxiliary switch is arranged to actuate a gate in the coin chute which then enables coins to be lodged in the chute by the next vehicle driver. At the moment the preceding vehicle triggers the switch to disengage the latch mechanisms, the switch also operates and opens the gate to permit the coins to enter the verifier, whereupon the latch-mechanisms are again actuated. The next vehicle can therefore commence to advance over the hinged platform before the preceding vehicle has completely negotiated the barrier.

[0025] In cases where the traffic light signals 35,36 are not considered a sufficient guide or deterrent to prevent the driver from atterpeing to negotiate the barrier, a viebie,pnysical barrier may be provided. In the embodiment illustrated in Figs, 1 and 2, this takes the form of a plate or board 50 provided with suitable markings to enhance its visibility and mounted on the obstruction unit 1. The board 50 is mounted on hinges 51 in a cavity 52 in the top surface 6 of the unit 1 so that, when the barrier is closed, it is rocked into the upright position shown in Fig. 2 where it is visible to a vehicle driver, and is conecaled in the cayity 52 when the driver is permitted to proceeds The board 50 may be actuated by a solenoid device (not shown) appropriately connected in circuit with the red and green traffic lights 35,36.

[0026] In some installations, the barrier may be required to control the flow of vehicles in one direction whilst permitting frec flow of vehicles in the reverse direction, for example, as in a car park having a single road or track for both entrance and exit to the car park. The auxiliary detecting means required to provide this facility is illustrated in Figs. 1 and 2. Hence, for movement of vehicles from right to left, as viewed in these figures, the barrier operates as previously described. However, the barrier must permit free flow of traffic in the reverse direction, that is from left to right, and, when a vehicle travels across the barrier in this direction, the platform 8 must therefore be automatically locked in its raised position. This is achieved by installing two auxiliary switch actuating bars 53,54 and associated switch mechanisms in the lead-in and -out sections 19,20. When a vehicle travels from left to right over the barrier and its front wheels engage the actuating bar 54, this is arranged to trigger a single switch connected to the locking solenoids S1 so as momentarily to energize the latter and lock the platform in its raised position. The latches are then subsequently released by operation of the actuating bar 53 as the vehicle moves off the platform 8. The actuating bar 53 and associated switch mechanism may be similar to the actuating bar 16 and its associated switch contacts so that the latches are only released when the rear wheels of the vehicle engage the bar 53. The actuating bars are adapted to trigger their associated switch mechanisms only upon engagement by a vehicle travelling from left to right over the barrier. When a vehicle negotiates the barrier in the opposite direction, the switch mechanisms remain unactuated.

[0027] Fig. 5 illustrates another embodiment in which the barrier is installed level with the road surface R instead of as a ramp projecting above it. In this embodiment, the unit 1 forming the step-like obstruction and the hinged platform unit 2 are installed in an excavation 55 in the road so that the top surface 6 of the unit 1 and the platform 8 are level with the adjacent road surface. This arrangement of the barrier operates and may be controlled in a similar manner to the embodiment described with reference to Figs. 1-4.

[0028] Whilst particular embodiments have been described, it will be understood that modifications can be made without departing from the scope of the invention as defined by the appended claims. For example, compression coil or tension springs may be utilised in place of the leaf springs 12 for urging the platform 8 into its raised position. When tension coils springs are utilised, these may be suspended from suitable framework projecting above the platform 8 at opposite sides thereof. Moreover, whilst the invention has been particularly described for controlling the movement of vehicles having two axles, it will be appreciated that either by utilising additional switches and relays or logic circuitry operating in response to a predetermined number of impulses, the barrier can be adapted for use with vehicles having additional axles and so that, upon travel of such a vehicle past the barrier, the platform 8 will not be unlocked until the rearmost set of wheels engage the actuating par when the barier is adapted to control the entrance or exit to a vehicle park intended also to be used by vehieles having more than two axles, the coin-operated cantrel device 34 may include an additional coin slot for such vehicles, the insertion of the prescribed coinage into this additional slot switching-in supplementary control circuitry which prevents release of the latches until the rearmost axle of the vehicle has advanced off the hinged platform.

Claims

1. A traffic barrier comprising a step-like obstruction (1) adapted to resist or prohibit the passage of a vehicle, a hinged platform (8) disposed in advance of the step-like obstruction and rockable between a lowered position and a raised position, in which its trailing edge (11) is adjacent the top (6) of the step-like obstruction, and means (12) urging the platform into its raised position, characterised by the platform (8) being depressible into its lowered position by a vehicle advancing over said platform from its leading (9) to its trailing edge (11), whereby the obstruction is presented to the vehicle to resist its advance, latch means (15) operable to lock the platform in its raised position, and control means for selectively actuating the latch means, whereby the platform may be locked in its raised position to permit a vehicle to advance over the obstruction from the platform, said control means being responsive to advance of the rearmost wheels of the vehicle onto the top of the obstruction to release the latch means.

2. A traffic barrier as claimed in claim 1, wherein the step-like obstruction (1) is arranged to project above an adjacent road surface (R) and the hinged platform (8), when in its raised position, is arranged as a ramp which leads from the road surface to the top (6) of the obstruction, and wherein a fixed ramp (3) is disposed on the opposite side of the obstruction to the platform and extends downwardly from the obstruction to the road surface (R) in order to permit a vehicle to return to the normal road surface after it has negotiated a barrier.

3. A traffic barrier-as claimed in claim 1, wherein the step-like obstruction (1) and the hinged platform (8) are disposed in an excavation (55) in a road with the top (6) of the step-like obstruction substantially level with the adjacent road surface (R) and the platform, when in its raised position, also substantially level with said road surface.

4. A traffic barrier as claimed in claim 1, 2 or 3, wherein the step-like obstruction (1) and the hinged platform (8) are prefabricated as two separate units (1,2) which can be instalted in justaposed relation in order to construct the trarfic barrier.

5. A traffic barrier as claimed in any one of the preceding claims, wherein the control means include a coin, token, card or ticket operated device (34) positionable in advance of the hinged platform (8) and responsive to the insertion of one or more prescribed coins or tokens or to the scanning cf a prescribed ticket or card to actuate the latch means (15) and lock the platform in its raised pesition.

6. A traffic barrier as claimed in any one of the preceding claims, wherein the control means includes detecting means (16,41,42) disposed on or adjacent the step-like obstruction (1) and responsive to movement of the rearmost wheels of a vehicle on to the top surface (6) of the obstruction in order to release the latch means (15).

7. A traffic barrier as claimed in any one of the preceding claims, wherein the control means includes first auxiliary detecting means (54) disposed rearwardly of the step-like obstruction (1) and arranged to detect the front wheels of a vehicle negotiating the barrier in a reverse direction, whereupon to actuate the latch means (15) so as to lock the platform (8) in its raised position, and second auxiliary detecting means (53) disposed forwardly of the leading edge (9) of the platform and operable by the rearmost wheels of the vehicle so as to release the latch means, thereby permitting unhindered flow of vehicles in said reverse direction.

8_. A traffic barrier as claimed in claim 6 or 7, wherein the main and auxiliary detecting means comprises actuating means (16) movable by the wheels of a vehicle negotiating the barrier and adapted to actuate switch means (41,42).

9. A traffic barrier as claimed in any one of the preceding claims, wherein the latch means (15) comprises at least one solenoid-operated latch member (21) mounted on the step-like obstruction (1) and arranged to engage a cooperating detent (13) on the hinged platform (8), when the latter is in its raised position.

10. A traffic barrier as claimed in claim 9, wherein the or each latch member (21) is controlled by two solenoid devices (S1,S2), one of which (S1) is adapted to advance the latch member into its locking position and the other of which (S2) is adapted to retract the first solenoid device and the latch member to their release positions.

11. A traffic barrier as claimed in any one of the preceding claims, wherein the latch means (15) includes a fail-safe device (S3) which is adapted to actuate the latch means and lock the platform (8) in its raised position when the electrical supply is switched-off or in the event of failure of the electrical supply.

12. A traffic barrier as claimed in any one of the preceding claims, including a visual signal means (35,36,50) associated with the barrier for producing a visible indication of whether or not the platform (8) is locked in its raised position and the vehicle is authorised to negotiate the barrier.

13. A traffic barrier as claimed in claim 12, wherein the visual signal means comprises a visible barrier member (50) mounted on the step-like obstruction (1) and operable by the control means so as to move into a visible position projecting above the obstruction, when the latch means (15) is released, and to return to a substantially concealed and unobstructing position, when the latch means is actuated and a vehicle is permitted to negotiate the barrier.

Drawing